Mumford A D, Parry L J, Summerlee A J
Department of Anatomy, University of Bristol, School of Veterinary Science.
J Endocrinol. 1989 Sep;122(3):747-55. doi: 10.1677/joe.0.1220747.
Experiments were performed on anaesthetized, lactating rats to investigate the acute central actions of relaxin on blood pressure and vasopressin release. When compared with saline and control injections of isotonic protein extract, administration of relaxin into either the lateral or dorsal portion of the third ventricle caused a significant and sustained rise in arterial blood pressure. In contrast, relaxin administered to the ventral portion of the third ventricle caused only a short-term rise in blood pressure. Injections of relaxin into the fourth ventricle were without significant effect, suggesting that the central actions of relaxin on blood pressure are mediated by receptors restricted to the diencephalon or mesencephalon. A similar ventricular specificity was noted for the central relaxin-induced stimulation of vasopressin release as judged by concentrations of the hormone in the peripheral plasma. It is unlikely that the stimulation of vasopressin release is wholly responsible for the observed pressor effect observed. Lesion of the subfornical organ negated the pressor effect to relaxin injected into the dorsal region of the third ventricle, but did not affect the pressor response observed after injection of relaxin into the ventral portion of the third ventricle. These results demonstrate a biphasic action of centrally administered relaxin, with the response to dorsally placed third ventricle relaxin being mediated by the subfornical organ, and the response to ventral injections associated with an unknown structure of the ventral third ventricle wall.
在麻醉的哺乳期大鼠身上进行了实验，以研究松弛素对血压和血管加压素释放的急性中枢作用。与生理盐水和等渗蛋白提取物对照注射相比，向第三脑室的外侧或背侧注射松弛素会导致动脉血压显著且持续升高。相比之下，向第三脑室腹侧注射松弛素仅引起血压短期升高。向第四脑室注射松弛素无显著影响，这表明松弛素对血压的中枢作用是由局限于间脑或中脑的受体介导的。根据外周血浆中该激素的浓度判断，中枢松弛素诱导血管加压素释放也具有类似的脑室特异性。血管加压素释放的刺激不太可能完全导致所观察到的升压效应。穹窿下器官损伤消除了向第三脑室背侧区域注射松弛素的升压效应，但不影响向第三脑室腹侧注射松弛素后观察到的升压反应。这些结果表明，中枢给予松弛素具有双相作用，对背侧第三脑室松弛素的反应由穹窿下器官介导，而对腹侧注射的反应与腹侧第三脑室壁的未知结构有关。
